The invention concerns a seat, with at least one seat base part and at the least a back rest, which are secured on a seat carrier and is adjustable relative to the carrier by means of a positioning drive, wherein the positioning drive is in controlling communication with at least one body position sensor for advance or retraction of the at least one seat part and the at least one back rest part in accordance with the body position taken by a person on the seat or for retraction of the at least one seat part and at least one back rest as signaled by a body movement of the person sitting on the seat.
From EP 0 865 960 A1, the application is now aware of an automobile seat with a seat base part and a backrest part, that are pivotably connected together by a pivot pin or pivot axis and are guided on a seat carrier in guide elements. This known seat includes a stop transmission which holds the seat base part and the backrest part in different positions. This fixed seat position effecting stop transmission is energy absorbing in such a manner that the seat may during a rear collision or a frontal collision through crash generated forces transfer the user of the seat from a normal seat position to a safety position.
The previously known automobile seat offers the user in rear as well as frontal collision a high measure of safety. This allows the user of the previously known seat to place the seat in a desired position. To adjust the seat part and the backrest, however, the stop transmission must be released and the seat must be moved in the guide element of the seat carrier with a certain expenditure of energy. The safety and the comfort, which the known automobile seat provides the user in the seated and adjusting position is a tradeoff with the force and time expenditure, required by the user to place the seat in a desired position.
From DE 196 44 376 A1, an automobile seat of the known art is disclosed, in which the seat part and the backrest part are adjustable through a motorized positioning arrangement. In that patent, it is proposed that in the seat part and in the backrest part, which are described as seat components, individual pressure sensors and drives are located. The direction of action of said parts is dependent upon the seating position of a previous user and from the posture pressures of a present user at the start of the adjustment procedure.
The description of DE 196 44 376 teaches, that various parts of the vehicle seat can be adjusted individually or again, optionally by a loading of the pressure sensors. However, senseless adjustment movements are not excluded and the user is put to great effort, to find a sitting position which is both ergonomically favorable and comfortable.
Besides this, there is another generic type of vehicle seat known, in which multiple positioning drives are adjustable in relation to one another and in relation to a seat carrier placed on the vehicle floor. These positioning drives are to be activated by the user individually and separate from each other. Furthermore, the user can respectively adjust the seat base drive and the backrest drive until the relative positions of the seat base part and the backrest part appear to be comfortable. For the operation of these positioning drives, several activating switches have been installed in this differing vehicle seat. These switches are to be generally sequentially activated by the user, one after the other. Thus these seats, especially for a person not practiced in their use, can only be operated with a considerable expenditure of time and effort.
Thus the objective exists, of creating a seat of the generic type mentioned in the introductory passages, which seat is especially comfortable and in particular, easily manipulated, and which, by means of different adjustment motions, leads to an ergonomically favorable sitting position.
The achieving of this objective, in accordance with the invention, is to be found in a seat of the type described in the introductory passages, wherein at least one seat base part and at least a backrest part are adjustably movable by guide elements constrained to function within given limitations, i.e. hereinafter xe2x80x9cenforced guidesxe2x80x9d. In this way, the seat base part and the backrest part are pivotally connected to one another and the seat base part and the backrest part respectively, have guides spaced from the pivoting axis and are rotatable about the guide axes or guide pins, and the backrest part assigned positioning drives in particulars are simultaneously activated by a common enabling switch.
Because of the guidance of the seat base part and the backrest part in the form of enforced guide elements, and because of the pivoting connection of these parts, one with the other, an adjustment of one of said parts leads to a corresponding relative position of the other. Thus, through the formulation of these enforced guides, the individual adjustment movements can result in no unfavorable relative positions of the parts between one another, but in each case, ergonomic positions are arrived at. Thus, the user can very quickly make one adjustment which results not only in user comfort and at the same time, achieves a seating which is ergonomically correct.
The enforced movement correlation of the at least one seat part and/or the at least one backrest part can be an integral guidance, for instance elongated slots or tubes with internal, slidable members which provide very precise positioning means. Such positioning means simultaneously determine the respective position and thereby prevent swinging or wobble motions of such a seat.
The enforced guidance or the integral control of the at least one seat part and/or the at least one backrest part can be provided on both sides of the seat, so that correspondingly symmetrical force apportionment is made possible.
The positioning drive of the inventive seat is controllingly connected with at least one body position sensor. After the positioning drive has been activated, then the control signals can be transmitted to the positioning drive. Having received the signals, the positioning drive acts to synchronously move the seat base part and/or backrest parts in such a manner forward or back, as directed by the body position or the body movement assumed by the user, until seat base parts and/or the backrest parts properly contacts the body of the user, or approaches such contact. Thus the user need not, as far as body position is concerned, attempt and try various seating movements until the seat exhibits a comfortable seating position. Much better, the inventive seat moves to accommodate that body position which the user has been previously found to be comfortable and therefore has previously assumed that position or would like to so sit once again.
Because the seat base part and backrest part assigned positioning drives are simultaneously activated by a common enabling switch, the seat in accordance with the invention provides synchronous body positioning movement. Therefore the user can adjust to a previous body position, for example angle his legs and at the same time incline the upper body forward while the seat base part and the backrest part adapt synchronously to these body movements.
In this manner the common switch may be activated, for example manually activated or through a voice or sound recognition.
The inventive seat can, for instance, be designed as an office chair or similar type of seating furniture, wherein the seat carrier forms the legs of the chair. Since, in motor vehicles adjustable seating is already in common use, and the source of energy necessary for the positioning drives is available in the immediate vicinity of the seat, the seat may be advantageously employed as a vehicle seat.
It is possible for the seating surface to be formed from many parts and include, for example a seat base part, a lumbar section and a positionable backrest part.
A simple embodiment, in accord with the invention, provides that the body position sensor is designed as a proximity measuring device, which, advantageously is placed in the area of the seat. Such a device can, for instance, possess ultra sonic or infrared sensors, which are placed somewhere in the area of the instrument panel of a motor vehicle. The possibility also exists, however, that the proximity measurement device is based on inductive sensors, which detect the changes in a magnetic field or an electrical field which are associated with corresponding changes in position by body movement.
Additionally, or instead of, these, it can be of advantage is at least one body position sensor function as a pressure sensor or a pressure switch. Such a sensor activates or halts the positioning drive assigned to it as is appropriate for the under or overstepping of a specified pressure loading. In this arrangement, a preferred improvement of the invention is brought about, wherein at least one body position sensor, for example a pressure sensor or pressure switch, controls its matched positioning drive. Such pressure sensors can thus control even the movement direction of the positioning drive in a simple manner. Thus it is possible, that the body position sensor of this type reacts to pressure changes in such a manner, that the positioning drive with which it is connected adjusts the seat within a given time and in a proper direction, until the drive once again generates a defined averaged pressure at the corresponding body position sensor.
In order to be able control the required positional movements and body-fitting adjustments of the seat in good order, it is advantageous if a first body position sensor is placed in the backrest part, preferably located at shoulder height, and if a second body position sensor is placed in the seat base, particularly located in the forward, free, exposed end area.
Particularly, the combination with the enforced guidance of the seat base part and the backrest part, the interlinked connection and pivotal rotatability of said parts gives rise to a particularly comfortable embodiment of the invention. Furthermore, this makes possible that the seat base part and backrest part can be activated and controlled by the fewest possible positioning drives, which are possibly also smaller than the usual size. At the same time, in spite of the seat""s ability to adjust to different positions involving both the parts of the seat base or backrest, senseless, uncomfortable and especially unfavorable ergonomic positions of these parts relative to one another is avoided. Also dispensed with is the adjust and try method of escaping such unfavorable positions, which causes corresponding loss of time of the user.
It can be advantageous, if at least one positioning drive is equipped with a manual override drive. A further advantage is gained if the seat base part and/or backrest part can be set in the chosen sitting position especially by means of a position fixing apparatus. Such an embodiment permits a servo-subsupported placement of the seat or possibly a placement by the user of the seat with the manual override alone. Instead of the otherwise preferred positioning drive with self-limiting spindles, which make a fixed placement device superfluous, with this design incorporating the servo-positioning device, which, for instance, can be made as a toothed rod drive, and can coact with a fixed placement arrangement.
It is advantageous, when the seat carrier of the vehicle seat is adjustably held in relation to the vehicle floor by a positioning drive, that the positioning drive is in controlling connection with a control system and that the control of the vehicle seat is dependent on at least the person-based data of the chosen angle of inclination of the seat base part. If the body position sensor is designed as a pressure sensor, for instance, the load of the body weight of the user upon the seat base part can be determined. This can be converted by the control system to normal body sizing and subsequently the seat is so adjusted, relative to the vehicle floor, that the user has a sufficient leg room and/or sits at a proper distance from the windshield of the vehicle. Additionally, or instead of this, the chosen angle of inclination of the seat base part can be computed, compared with normal body sizes, and the seat subsequently positioned in relation to the floor.
A further embodiment of the invention can be comprised in that the body position sensor(s) is a travel or motion sensor. In this way, corresponding motions of the user can be measured for the extension of a defined adjustment of the individual parts of the seat and converted into corresponding positioning movements. These movements can moreover be input to memory, so that the respective favorable sitting position can be quickly found again after an intervening different positioning. A travel or movement measuring device permits, in the said operation, a precise conversion into a adjustment motion, because a sensitive activation is possible, especially if a correspondingly larger travel, as compared to a pressure sensor, leads to the respective displacement.
The body position sensor(s) can be a pivoting or a linear pick up for motion. For instance, a pivoted lever or a teeter bar or a plate movable at right angles to its surface, which is coupled with at least one potentiometer or the like measurement accepting device and coacts with the same. In this way, either by a teeter bar or a lever pivoted at one end, or a rotational potentiometer mounted on the rotating pin or even a linear potentiometer can be provided, which is also of advantage with a movable plate.
The sensor, provided for travel or motion of body position, in particular the pivotally or the linearly movable motion pickup, in this application, can be movable against a reset force into a displaced position, and by means of said reset force, for instance, a spring and/or the upholstery of the seat be moved back into a start position. This affords a particularly simple possibility of installing a body position sensor hidden inside the upholstery of a seat thus being not only space saving but also effective.